Manifold for an internal combustion engine fuel supply device

Abstract

 A manifold (1) comprising a first tubular body (2) with fittings (3) for metering valves; a second body (4) housed inside the first body (2) so as to define, with the first body (2), a conduit (5) for supplying fuel to the fittings (3); a wall (6) closing a first end of the first body (2); and a pressure regulator (7) closing a second end of the first body (2) and one end of the second body (4). The second body (4) comprises a first pipe (12) extending from the central portion of the first body (2) to the wall (6); a fuel inlet (13) for the first pipe (12), defined in the central portion of the first body (2); a hydraulic passage (14) defined, close to the wall (6), between the first pipe (12) and the conduit (5); a second pipe (15) extending from the central portion of the first body (2) to the pressure regulator (7); and a fuel outlet (16) for the second pipe (15), defined in the central portion of the first body (2).

Description

[0001] The present invention relates to a manifold for an internal combustion engine fuel supply device, and in particular to a manifold for supplying pressurized fuel to a number of fuel metering and atomizing valves.

[0002] Manifolds of the above type normally comprise a first tubular body with a number of fittings for the valves; and a second tubular body housed coaxially inside the first body so as to define, between the first and second bodies, an annular conduit for supplying fuel to the fittings. The first and second bodies are closed at a first axial end by a pressure regulator for maintaining the fuel pressure in the supply conduit below a given value, and at a second axial end by cap in which are formed a first duct between the fuel tank and the annular supply conduit, and a second duct between the second tubular body and the tank. On some manifolds, the second duct is formed in the first tubular body, at the pressure regulator seat.

[0003] Manifolds of the aforementioned type present several drawbacks, foremost of which is the fact that delivery and drainage of the fuel are defined at one axial end of the manifold, which, in addition to limiting assembly of the manifold, also results in greater length and in difficulties in hydraulically connecting the manifold and tank. Moreover, the sealing efficiency of the ducts formed in the cap or close to the pressure regulator is invariably reduced with time, thus resulting in fuel leakage.

[0004] It is an object of the present invention to provide a manifold for an internal combustion engine fuel supply device, designed to overcome the aforementioned drawbacks.

[0005] According to the present invention, there is provided a manifold for an internal combustion engine fuel supply device, comprising a first tubular body with a number of fittings for fuel metering and atomizing valves; a second body housed inside said first body so as to define, with said first body, a conduit for supplying fuel to said fittings; a wall for closing a first axial end of said first body; and a pressure regulator mounted so as to close a second axial end of said first body and a first axial end of said second body; characterized by the fact that said second body comprises:
   a first pipe extending from a central portion of said first body to said wall;
   a fuel inlet for said first pipe, defined in said central portion of said first body;
   a hydraulic passage defined, close to said wall, between a first axial end of said first pipe and said conduit;
   a second pipe extending from said central portion of said first body to said pressure regulator, a portion of which closes a first axial end of said second pipe; and
   a fuel outlet for said second pipe, defined in said central portion of said first body.

[0006] A preferred, non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawing showing a longitudinal section of a manifold, indicated as a whole by 1, for an internal combustion engine fuel supply device.

[0007] Manifold 1 comprises a tubular body 2 with a longitudinal axis A and a number of fittings 3 for known fuel metering and atomizing valves (not shown); and a second, externally cylindrical, body 4 housed substantially coaxially inside first body 2 so as to define, with first body 2, an annular conduit 5 defined by the respective inner and outer surfaces of bodies 2 and 4, and communicating with fittings 3 for supplying fuel to said valves. Body 2 is closed at a first axial end by a member consisting of a known pressure regulator 7, and at a second axial end by a wall 6. Pressure regulator 7 is mounted so as to close said first axial end of body 2 and a first axial end of body 4; provides for maintaining the fuel pressure in conduit 5 within a given range; and presents a spring by which it is locked to body 2.

[0008] Body 4 is formed in one piece, and presents:
   a solid central portion 11 in the central portion of body 2;
   a first pipe 12 extending from a first side of central portion 11 to wall 6 where a first axial end of pipe 12 is engaged internally by a cylindrical projection 9 extending from wall 6;
   an inlet 13 for pipe 12, defined between a second axial end of pipe 12 and central portion 11;
   a number of through slots 14 formed close to the first axial end of pipe 12, for hydraulically connecting pipe 12 and conduit 5;
   a second pipe 15 extending from a second side, opposite the first, of central portion 11 to pressure regulator 7, a component part of which closes a first axial end of pipe 15; and
   an outlet 16 for pipe 15, defined between a second axial end of pipe 15 and central portion 11.

[0009] Manifold 1 also comprises:
   tabs 29 along conduit 5, for centering pipes 12 and 15 in a given position in relation to body 2;
   a first hydraulic joint 17 having a first portion 19 fitted in sealed manner to inlet 13; and a second portion 20, outside body 2, for supporting one end of a pipe 18 from the tank; and
   a second hydraulic joint 21 having a first portion 23 fitted in sealed manner to outlet 16; and a second portion 24, outside body 2, for supporting one end of a pipe 22 to the tank.

[0010] The central portion of body 2 presents two threaded holes 25, one engaged by a central, externally threaded portion 26 of joint 17, and the other engaged by a central, externally threaded portion 27 of joint 21.

[0011] In the example embodiment shown, pipes 12 and 15 are coaxial with each other, and present substantially the same length and diameter; and the longitudinal axes B and C of joints 17 and 21 (and hence holes 25) are perpendicular to axis A and lie in the same plane.

[0012] Bodies 2 and 4 may be made of metal, preferably rheocast aluminium, or plastic; and body 2 is formed, preferably pressed, in one piece with wall 6.

[0013] Manifold 1 is assembled by first inserting body 4 inside body 2 so that the axial end of pipe 12 is engaged by projection 9, in which position, inlet 13 and outlet 16 are coaxial with holes 25. This is followed by assembly of pressure regulator 7 which closes and seals body 2, and a portion of which engages said first axial end of pipe 15. Finally, joints 17 and 21 are assembled by screwing respective central portions 26 and 27 inside holes 25.

[0014] In actual use, by means of a pump (not shown), fuel is fed from the tank along pipe 18, through joint 17 and inlet 13 to pipe 12, and through slots 14 into conduit 5 where it is distributed to the metering valves. Any increase in pressure along conduit 5, over and above the setting of pressure regulator 7, is counteracted by pressure regulator 7 feeding the fuel along pipe 15, through joint 21 and along pipe 22 back to the tank.

[0015] The advantages of the present invention will be clear from the foregoing description.

[0016] In particular, by virtue of the fuel inlet and drain outlet being formed in the central portion, the manifold according to the present invention provides for troublefree assembly inside the engine compartment, for reducing overall axial size, and for troublefree hydraulic connection of the manifold and pipes 18 and 22. Moreover, it provides for incorporating the fuel delivery and recirculating pipes in one body; and for simplifying manufacture of body 2 by eliminating the cap opposite pressure regulator 7. From the functional standpoint, the path along which the fuel is fed provides for flushing and so preventing deposits from accumulating in the portion of body 2 close to wall 6. Finally, the manifold according to the present invention provides for more reliable hydraulic sealing, thus greatly reducing the risk of fuel leakage.

[0017] To those skilled in the art it will be clear that changes may be made to manifold 1 as described and illustrated herein without, however, departing from the scope of the present invention.

[0018] For example, pipes 12 and 15 may be of different lengths, and need not necessarily be coaxial; fuel passage from pipe 12 to conduit 5 may be enabled by means of recesses formed at said first end of pipe 12, or by forming pipe 12 of such a length as to allow a given clearance between the first axial end of pipe 12 and wall 6; joints 17 and 21 may be offset, i.e. holes 25 may present respective axes in different planes; the distance between joints 17 and 21 (and hence between holes 25) may be other than as shown; and body 4 and/or body 2 may be formed in a number of, preferably modular, parts.

Claims

1. A manifold for an internal combustion engine fuel supply device, comprising a first tubular body (2) with a number of fittings (3) for fuel metering and atomizing valves; a second body (4) housed inside said first body (2) so as to define, with said first body (2), a conduit (5) for supplying fuel to said fittings (3); a wall (6) for closing a first axial end of said first body (2); and a pressure regulator (7) mounted so as to close a second axial end of said first body (2) and a first axial end of said second body (4); characterized by the fact that said second body (4) comprises:
   a first pipe (12) extending from a central portion of said first body (2) to said wall (6);
   a fuel inlet (13) for said first pipe (12), defined in said central portion of said first body (2);
   a hydraulic passage (14) defined, close to said wall (6), between a first axial end of said first pipe (12) and said conduit (5);
   a second pipe (15) extending from said central portion of said first body (2) to said pressure regulator (7), a portion of which closes a first axial end of said second pipe (15); and
   a fuel outlet (16) for said second pipe (15), defined in said central portion of said first body (2).

2. A manifold as claimed in Claim 1, characterized by the fact that it comprises:
   a first hydraulic joint (17) having a first portion (19) fitted to said inlet (13); and a second portion (20), outside said first body (2), for supporting one end of a third pipe (18) from the fuel tank; and
   a second hydraulic joint (21) having a first portion (23) fitted in sealed manner to said outlet (16); and a second portion (24), outside said first body (2), for supporting one end of a fourth pipe (22) to said tank.

3. A manifold as claimed in Claim 2, characterized by the fact that said second body (4) comprises a solid central portion (11); said first pipe (12) extending from a first side of said central portion (11); and said second pipe (15) extending from a second side, opposite the first, of said central portion (11).

4. A manifold as claimed in Claim 3, characterized by the fact that said inlet (13) is defined between said first pipe (12) and said first side of said central portion (11); and said outlet (16) is defined between said second pipe (15) and said second side of said central portion (11).

5. A manifold as claimed in at least one of the foregoing Claims, characterized by the fact that said first (12) and second (15) pipes are coaxial with each other.

6. A manifold as claimed in Claim 5, characterized by the fact that said first (12) and second (15) pipes are coaxial with said first body (2).

7. A manifold as claimed in Claim 2, characterized by the fact that the longitudinal axes (B and C) of said hydraulic joints (17 and 21) are perpendicular to the longitudinal axis (A) of said first body (2).

8. A manifold as claimed in Claim 7, characterized by the fact that said longitudinal axes (B and C) of said hydraulic joints (17 and 21) lie in the same plane.

9. A manifold as claimed in any one of the foregoing Claims, characterized by the fact that said passage comprises at least one through slot (14) formed close to the first axial end of said first pipe (12).

10. A manifold as claimed in any one of the foregoing Claims from 1 to 8, characterized by the fact that said passage comprises at least one recess formed at the first axial end of said first pipe (12).

11. A manifold as claimed in any one of the foregoing Claims from 1 to 8, characterized by the fact that the first axial end of said first pipe (12) is a given distance from said wall (6), thus defining said passage.

12. A manifold as claimed in any one of the foregoing Claims from 1 to 10, characterized by the fact that said second body (4) is formed in one piece.

Drawing